I never heard of full band kit. Does that mean you get all the dlc songs for one price? Pretty expensive but I'm guessing you'd save money in the long run.
The full band kit gets you one of the new guitars, the new drums, a microphone, and Rock Band 4 with the Rivals expansion. If you pre-order the bundle you get those 10 songs for free, and if you get it from Amazon you'll get two additional songs on top of the 10. If you don't pre-order, you can still get those songs as dlc a few weeks after release for $1.99 a piece (or cheaper if they do a pack with them).
The new full band kit is actually cheaper than the full band kit when RB4 launched last year.
No, it's just poor wording on Harmonix's part.In the thing I ready the other day, Harmonix said online multiplayer comes to the base game in a free patch in December. So you don't have to buy the expansion.
Online is a free update for owners of Rivals, not for all owners of Rock Band 4.